Undifferentiated carcinoma of the duodenal ampulla.

This report demonstrates a case of undifferentiated carcinoma of the duodenal ampulla. A 74-year male experienced jaundice lasting for 3 weeks. An upper gastrointestinal series demonstrated a polypoid, ovoid filling defect in the second portion of the duodenum, and duodenoscopy disclosed a protruding mass involving the orifice of the papilla of Vater. Cholangiography demonstrated obstruction due to compression in the terminal common bile duct. Pylorus-preserving pancreatoduodenectomy was performed on the diagnosis of ampullary carcinoma. The gross specimen showed a polypoid mass, measuring 3.5 cm in diameter, in the ampulla, located mainly in the duodenal submucosal layer and invading the terminal common bile duct. Histologically, the tumor was small cell type, undifferentiated carcinoma, arising from the duodenal epithelium adjacent to the ampulla.